Device for obtaining earth samples

ABSTRACT

TO BE CLOSED WHEN SAID TUBE IS WITHDRAWN FROM THE EARTH BROKEN LOOSE FROM SAID OUTER CASING.   DEVICE FOR OBTAINING EARTH SAMPLED COMPRISES AN INNER TUBE HAVING CUTTING MEANS AT ITS FORWARD END AND ADAPTED TO BE DRIVEN INTO THE EARTH, FINGERS WITHIN THE TUBE FOR DETACHING A CORE THEREWITHIN WHEN THE TUBE IS PULLED UP, AN OUTER CASING FRANGIBLY ATTRACHED TO THE INNER TUBE, PASSAGEWAYS BETWEEN THE TUBE AND CASING FOR RECEIVING WATER AND, IN A PREFERRED EMBODIMENT, VALVE MEANS FOR CONTROLING THE ADMISSION OF WATER TO SAID PASSAGEWAYS ADAPTED

Feb. 13, 1973 T 3,716,107

DEVICE FOR OBTAINING EARTH SAMPLES Filed March 10, 1971 2 Sheets-Sheet 2fi a 2 a 27) 4 I8 Feb. 13, 1973 J. LIAUTAUD 3,716,107

DEVICE FOR OBTAINING EARTH SAMPLES Filed March 10, 1971 2 Sheets-Sheet 1United States Patent 3,716,107 DEVICE FOR OBTAINING EARTH SAMPLES JeanLiautaud, Paris, France, assignor to Entreprise de Recherches etdA-ctivites Petrolieres (Elf), Paris, France Continuation-impart ofabandoned application Ser. No.

887,657, Dec. 29, 1969. This application Mar. 10, 1971,

Ser. No. 122,771

Int. Cl. E21b 9/20 US. Cl. 175-248 Claims ABSTRACT OF THE DISCLOSUREDevice for obtaining earth samples comprises an inner tube havingcutting means at its forward end and adapted to be driven into theearth, fingers within the tube for detaching a core therewithin when thetube is pulled up, an outer casing frangibly attached to the inner tube,passageways between the tube and casing for receiving water and, in apreferred embodiment, valve means for controlling the admission of waterto said passageways adapted to be closed when said tube is withdrawnfrom the earth and broken loose from said outer casing.

This is a continuation-in-part of application Ser. No. 887,657, filedDec. 29, 1969.

SUMMARY OF THE INVENTION This invention relates to apparatus for use inobtaining samples from the earth, particularly the sea bed.

The invention has for its object the provision of improved apparatus forthis purpose.

It is one of the principal objects of this invention to provide asampler device which is adapted to be driven into the sea bed by meanswhich impart it to a high initial speed, and which can then readily bewithdrawn from the sea bed, bringing with it the required sample.

A further object of the invention is the provision of such a samplerdevice which can easily be withdrawn from the sea bed even if it hasbeen driven into the latter to a substantial depth.

According to the invention a sampling device is provided which isadapted to be fixed into the earth to take a sample therefrom, whereinthe device comprises a tube having a cutting part at its forward end,guide-fins towards its other end and separating fingers towards itsforward end for separating a sample within the tube when a rearward pullis applied to the latter, wherein the tube is surrounded by a jacketwhich is initially attached to it but which is adapted to be left behindin the cavity left in the earth when the tube containing the sample iswithdrawn, the jacket then providing a lining for the cavity andfacilitating the retraction of the tube with its sample.

A first form of device for taking samples from the earth when it isprojected into the latter is constituted by a cylindrical tube which isprovided at its forward portion with a cutting element or part which isprovided internally with separating fingers actuable by a pull appliedto the sampling tube, the said tube being equipped with guide-fins andbeing surrounded by a connecting jacket, said jacket being adapted to beleft in position in the cavity left when the sample is removed bypulling on the device, the said jacket also providing a lining for thecavity and facilitating withdrawal of the tube with a sample in it by apull applied to the tube.

In this embodiment, water is allowed to circulate between the outer wallof the main tube and the jacket surrounding it, so as to ensure thefilling of the cavity formed when the plug-sample is removed under theetfect of the pull applied to the sampling tube.

3,716,197 Patented Feb. 13, 1973 While such devices are perfectlysuitable for the collection of consolidated samples, their use isunsatisfactory when collecting unconsolidated samples, because the seawater Washes the core sample away during the raising of the sampler.

In certain slow-percussion samplers, there already exist pistons whichshift during sampling and block off the top of the sampler, thusprotecting the sample from being washed away. However, such samplerscannot be operated quickly, because the penetrating impact is caused bythe dropping of metal weights.

Fast-percussion samplers cannot be fitted with such pistons, which wouldhave the elfect of immobilizing them before they come into contact withthe sea bed.

The present invention provides a method of removing this drawback, byshutting off the underwater percussion sampler when it has completed itsdownward movement, without the use of a piston.

For this purpose, the water-circulation passages are fitted with one ormore mobile shut-01f valves, of an elastomer material, for instance.

According to one embodiment of the invention, the valves, in the openposition, are secured by means of one end of a component which pivotsaround a fixed point, the other end being connected to a bolt on thecasing.

According to another embodiment of the invention, the releasing andclosing of the valves are controlled by the outer casing sliding alongthe sampler member.

According to yet another embodiment of the invention, the sliding of theouter casing along the sampler member is caused by the pull exerted onthe sampler to withdraw it from the sea bed.

The sampler according to the present invention may also contain a waterintake in the releasable outer casing, near the top of the said casing.

The invention will be better understood from the following descriptionof two embodiments thereof, taken in conjunction with the accompanyingdrawings.

In the drawings:

FIG. 1 is a side view of a first embodiment of the invention, partlybroken-away, and partly as a longitudinal section taken through thesampler device;

FIG. 2 is a partial transverse cross-section through one-half of thedevice shown in FIG. 1; and

FIG. 3 is an axial cross-sectional view illustrating an embodimentcomprising a shut-off device.

The sampler device shown in FIG. 1 comprises a main tube 1 which isconnected by means of screw-threads to a body 2, this connection beingat the upper part of the tube 1. a

At its lower part the main tube 1 carries a cutting element 3. ThisCutting element has a tapered profile to enable it to penetrate into thesea bed without too much resistance. The tube 1, the outer part of whichis formed with ribs and channels (see FIG. 2), is surrounded by a jacket4 in such manner that there is unoccupied space between the outer partof the tube 1 and the inner surface of the jacket 4.

At its lower part the main tube 1 carries a sleeve 6 which supports aninner jacket 5, which might extend along the entire length of thedevice. The purpose of this sleeve 5, which is connected to the body 2,is to accommodate the sample taken from the sea bed. At the bottom ofthe sleeve 5 the sleeve 6 carries steel wires 7, which form a spider andwhich are intended to keep the pluglike sample in position once it hasbeen obtained. The sleeve 6 also carries at its lower end an arrangementof separating fingers 8, which rock about spindles carried by thesampling device and which cut into the ground when a pull is applied tothe device to withdraw it.

The forward or lower portion 9 of the jacket 4 is arranged to form acontinuation of the cutting element 3. Passages 10 and 11 enable seawater to circulate between the tube 1 and the jacket 4 to fill the space12, which is left when the plug sample is retracted. When the device isdriven forward, the outer jacket 4 is locked to the assembly by means ofa stop 13.

The device also comprises guide fins 14 which have holes 15 forattaching the device to the firing system. The numeral 16 indicatespassages in the body 2 which enable water to be delivered to thepassages 11 and 12 and to the space 17 between the main tube 1 and thejacket 4. The numeral 18 indicates shear-pins which temporarily attachthe jacket 4 to the rest of the device. These shearpins could bereplaced by check screws. Their function will be explained later.

Finally, a centering element 19 enables the assembly to be fitted andaligned as a whole in the firing system.

In FIG. 2, the numeral 1 indicates the main tube, the outer portion ofwhich is formed with ribs and channels. The numeral 4 indicates theouter jacket. The numeral 20 indicates the ribs, while the spacesbetween the main tube 1 and the outer jacket 4 provided by the channelsare shown at 17.

This sampling device operates as follows:

The assembly is placed in a firing gun, and when it is in position, theexplosive that drives the device towards the sea bed is detonated. To bemost effective, the apparatus should preferably be positionedapproximately two metres from the sea bed so that the sampling device,before touching the sea bed, will have reached an initial high speed.The sampling device is braked to only a slight extent during its travel,as a result largely of the form of the passages 16, which aresubstantilly an extension of the sample-carrying tube and which have atotal cross-section greater than that of the tube. The water can thuscirculate more freely and the braking action is slight.

When the sampling device enters the sea bed, the head 3 enables it tobury itself in the manner of a driven stake, and the sample fills theinterior of the device, the outer jacket 4 exercising a rubbing actionas it slides into the sea bed.

The sampling device becomes deeply buried in the sea bed and is thenbraked by the fins 14 which have also acted as guiding and stabilizingmeans for the device. Once penetration has been effected, a pull isapplied to the sampling device with the help of cables previously passedthrough the holes 15. Under the combined effect of this pull andfriction of the sea bed, the pins 18, or the check screws which canreplace them, disengage the jacket 4, which then remains in the cavityformed by the tubular construction of the device. The fingers 8 rock andpart off the plug-like sample in the jacket 5, and the mobile spider '7or wires retains the plug in the jacket 5.

Also, water can circulate freely by way of the passages 16, 11 and 10,and can take the place of the plug-like sample. Retraction can then becarried out without great effort and a pull of a few tons usuallysuffices to disengage the sampling device from the sea bed.

For the purpose of recovering the sample, the body 2 is removed and thetube 5 can then be readily disengaged so that a suitable representativesample of the sea bed can be obtained in a simple manner.

In FIG. 3, the left half of the figure is a cross-section taken throughone-half of the upper part of a percussion sampler equipped with ashut-off system controlled by the sliding of the releasable outer casingwith the shut-off system in the open position, occupied during thedescent of the sampler and its penetration into the sea bed, while theright half is an axial cross-sectional view showing the same system inits closed position, occupied during withdrawal of the sampler, withreference numerals 1, 2', etc. corresponding to 1, ,2, etc. on theleft-hand side.

The main component of the sampler 1 is screwed on to the body 2 formingthe head of the sampler, and which receives the percussion impact at 19,from a propelling device, not shown. Two passages 16 allow the column ofwater occupying the sampler tube 5 to be emptied out at the moment ofpercussion, hindering the sampling operation as little as possible. Thesliding casing 4, which remains attached to the sides of the hole whenthe sampler is raised to the surface after sampling, and which makes itsextraction from the sea bed easier, is fixed to the coupling 2 by shearscrews 18.

The shut-01f valve, shown in the left-hand part of the figure in theopen position, consisting of a plug 21, of an elastorner material, forinstance, fixed on an axis 30 to a seesaw lever 23 which rotates round afixed point 22, and the other end of which 24 is held, in the openposition, by a bolt 25; this bolt slides in guides 26, and is connectedat 27 to the releasable sliding casing 4. A drawback spring 28 forcesthe plug 21 on to the seat 29 of the passage 16 as soon as the bolt 25is drawn downwards by the casing 4. To ensure hermetic shutting-off ofthe passages, each plug 21 has a slight degree of play on its axis 30,so that it can fit itself into the passage. Cables such as 31 allow thesampler to be withdrawn. There is also a water intake 32, letting waterflow between the outer casing 4 and the sampler 1, and allowing it to beremoved without disturbing the sampler.

The device operates as follows.

When the sampler penetrates into the sea bed, the shutoff valve is inthe open position shown at 21. As soon as penetration is completed, thesampler is pulled up by the cables 31, to withdraw it. Under thecombined effect of this pull and the friction from the sea bed, thescrews 18 snap, freeing the casing 4, which remains attached to thesides of the hole. The bolt 25, which is fixed to the casing 4, slidesdownwards through the slides 26, to the position 25'. The lever 23 isthereupon freed, and the drawback spring forces it into the position23', so that the plug 21 comes against the seat 29 of the passage 16,blocking it off. With the passage blocked, water no longer circulatesinside the casing 5 of the sampler, preventing the soil sample frombeing washed away by seawater throughout the raising of the sampler.

In another embodiment of the invention, not illustrated, the bolts 25,instead of being moved by the casing 4 sliding along the sampler 1,following the pulling of the sampler by the cables 31 in order to raiseit to the surface, may be moved directly as the result of such pulling,by means of a simple lever which operates as soon as an upward pull isactually exerted on the cables 31.

What is claimed is:

1. A sampling device adapted to be driven into the earth to take asample therefrom, in which said device comprises a tube having cuttingmeans at its forward end, external guide fins toward its other end, andinternal separating fingers toward its forward end for separating asample within the tube when a rearward pull is applied to said tube, ajacket encircling said tube, means frangibly attaching said jacket tosaid tube, whereby said jacket may be separated from said tube and leftbehind in the earth when the tube containing the sample is withdrawn,and passages permitting water to flow into and out of said tube.

2. A sampling device as claimed in claim 1 in which the tube iscylindrical with longitudinal ribs and channels formed in its outersurface.

3. A sampling device as claimed in claim 1 comprising valve means whichcontrols the entry of water into said passages, and stop means mountedon said tube which holds said valve means in open position as long assaid tube remains attached to said jacket.

4. A sampling device as claimed in claim 3 comprising spring meansmounted to bias said valve means toward a closed position, said stopmeans being mounted to release said spring when said tube and jacket areseparated.

5 6 5. A sampling device as claimed in claim 3 compris- 2,583,965 1/1952Page et a1. 1756 ing a simple lever mounted to close said valve means3,331,453 7/1967 Kermabon 1756 when said tube is separated from saidjacket. 3,372,760 3/ 1968 Raymond et References Cited 5 MARVIN A.CHAMPION, Primary Examiner UNITED TA PATENTS R. E. FAVREAU, AssistantExaminer 3,295,616 1/1967 Charlton et al. 1755 US. Cl. X.R.

3,561,546 2/1971 Craig 1755 175-5

